We knew Jovan Belcher's mother was there on the morning the Kansas City Chiefs linebacker murdered his girlfriend before he drove to the team's practice facility and killed himself. We also knew she had heard an argument and that she had called 911 call to report that Kasandra Perkins had been shot. Now, the New York Post is reporting that Belcher's mother, Cheryl Shepherd, told cops she overheard the couple fighting about whether Belcher was the father of the couple's 3-month-old daughter, Zoey, just before she heard gunshots:

"The mother believed that there was an issue over whether [Belcher] was the father," said a source close to the Chiefs with knowledge of the situation.

"She said he [believed he] wasn't necessarily the father of the child."

A Kansas City law-enforcement source confirmed, "She told [police] there was a question about the paternity."

It's unclear if the paternity issue was the reason for the final, violent end of the troubled relationship between Belcher, 25, and Perkins, 22.

"But the implication was that [paternity] was what the two of them were fighting about - that the baby might not have been his," a source said.

The Post also spoke to a woman who had answered Shepherd's cell phone, but the woman declined to comment and did not reveal her name. The NFLPA did not respond to the newspaper's numerous requests for comment about whether the baby's paternity would influence the survivor benefits the child is due to receive. Kansas City police also have no plans to make Zoey's paternity part of their investigation.

"That would not be something they're going to investigate," said Sgt. Marisa Barnes. "It's a ‘he-said, she-said' so there's no way to investigate. It would be nothing more than a civil matter."

Update (1:34 p.m.): Per USA Today, Kansas City police spokesman Darin Snapp denied the Post's report. "I talked to the lead detective, and he said not one witness has come forward mentioning paternity," Snapp said.